This invention relates to electrical power sources and more particularly to a radioisotope photoelectric generator which may be used as a self-contained remote power source.
Heretofore, various types of electrical generators and batteries have been used for various uses. Remote power sources include such diverse sources as conventional batteries, radioisotope thermoelectric generators (RTG), and solar cell arrays. Batteries have the obvious disadvantage of limited amounts of energy available and thus they must be recharged periodically. Solar cell arrays have many significant advantages (particularly for spacecraft) but even when used with storage cells they cannot supply reliable power on earth because of cloud cover and similar problems.
A highly reliable system for remote applications such as the recent space missions to the outer planets or for remote military requirements is the RTG. The RTG is the most similar power source to the present invention. Both use, as their energy sources, radioactive isotopes and therefore have the potential for very high reliability. The RTG, however, has the disadvantages of low efficiency (.about.4%) and very high operating temperature required and, for applications where a high voltage source is required, a further conversion from the low voltages produced by the RTG (generally less than 100 volts) to the desired high voltage is required at a further sacrifice in efficiency. As used in this disclosure "high Z" or "high atomic number" is defined as Z&gt;46 and "low Z" or "low atomic number" is defined as Z&lt;23.